'Hey Bird, What Are You Doing With That Butt?'

While we're in the neighborhood: a new study has found that birds' nests lined with cigarette butts help keep the residents warm, snug and pest-free. Scientists at St. Andrews University in Scotland say that nicotine and other chemicals in the discarded butts act as natural pesticides against mites. And the cigarette filters provide the nest with insulation against the cold. The study was conducted in Mexico City, where butts abandoned and smashed on the streets are plentiful, so hard bitten urban birds are more likely to be happy nesters than those in the country. Cigarette companies are hard-pressed to put anything appealing in their ads these days on a product that by law must be bannered: Surgeon General's Warning: Smoking causes Lung Cancer, Heart Disease, Emphysema, And May Complicate Pregnancy. Maybe now they can add: It's For the Birds. Transcript provided by NPR, Copyright NPR.